1. Field of the Invention
The present invention relates to a new device for controlling or sensing consumption of fuel in internal combustion engines, preferably in diesel engines, wherein the device is able to operate autonomously and to measure the real consumption by considering not only the fuel fed to the fuel injectors but also the exceeding fuel that is returned back to the fuel tank, this measuring being also adjusted by the temperature of fuel. The invention also provides a method fro measuring the fuel consumption in internal combustion engines.
2. Description of the Prior Art
Control or measuring of fuel consumption during the running or operation of the engine is something that car manufacturers have pursued because this parameter, fuel consumption, has become of very importance in the daily use of a vehicle, either a familiar one or a commercial truck, etc. In commercial transportation, the fuel consumption is a parameter importantly involved in the operation costs of the business.
There are well known measuring systems employing a fuel flow meter installed in a fuel line before the fuel inlet to the engine such as the fuel injectors. In diesel engines, however, this way of measuring the consumption leads to erroneous figures because there are some variables that are not taken into account to calculate a real consumption figure. For example, the amount of fuel fed to the fuel injectors are not entirely consumed because only part of the fuel passing through the injectors are injected into the combustion chamber, namely the cylinder of the engine, while other part continues circulating out of the injectors via a return line back to the fuel tank of the engine system.
Under the above circumstances, some installers or mechanics close, remove or by-pass the fuel return coming from the injectors to the fuel tank in order to attempt to get correct measures. One of the drawbacks of making a by-pass in the fuel return is that the conditions of operation of the fuel pump is altered and the pressure is modified in the return circuit. This is an important drawback because the return line passes trough a return valve that controls and guarantees the correct pressure in the injection chamber of the pump with undesired results in the engine operation.
In addition to the foregoing, if the return line is closed, one of the functions of this return, namely the refrigeration of the injection system, is cancelled with the consequent premature deterioration of the system. An additional drawback is that the return line also actuates to keep the injection pump free of fuel vapour bubbles generated into the injection chamber, wherein the return line brings and conducts the bubbles into the fuel tank. Finally, some is the known sensors, employed in conventional fuel flow meters, are not capable of adjusting detected values according to variables involved in the system as well as these sensors always require of a display for analysis and view of the required information.
Considering the above, it would be very important to have a new device or system for calculating the correct fuel consumption of an engine without altering the operation conditions of the engine, without requiring of complex installations, with autonomous operation, with no requirements of displays for information, and capable of storing information in a sensor to be accessible when requested.